there are medical mysteries all around us. today, we are going to take you to a place patients go when no one has been able to tell them what's wrong. they are real medical mysteries with real people. let's get started. >>> what if you got sick with a life-threatening condition, but your doctor doesn't know why or what to do. i'm going to take you inside a hospital, where a team of the most brilliant minds in medicine solve illnesses. it's outside the capital. you are going to meet amazing patients. maryland. deep inside this nih complex, dr. william gahl leads a team of doctors. they are the best in the world. together, they focus their vast expertise to save patients lives. they are detectives in ter ch of clues to solve mysteries no other doctors could solve. >> you are talking about patients seen by some of the best in the country here. they are good clinicians and diagnostic doctors everywhere. you are taking the hardest, the most challenging cases of all. >> we expect a high failure rate. we expect a success rate of 10%